On 22 January 2005 07:14, Ashley Yakeley wrote:

There's been a lot of discussion here and other lists of replacing System.Time, and indeed Simon M. is working on a replacement proposal:

http://www.haskell.org/~simonmar/time/NewTime.html http://www.haskell.org/~simonmar/time/NewTime.hsc

Rather than talk about specific Haskell code, I'd like to discuss the measurement of time in general, how these concepts might be expressed in Haskell, and what people might want from a time library. Rather than propose anything, I want to try to ask some of the right questions.

I'd like to join the others in saying thanks for a fine summary, Ashley. Nice work! On the subject of the NewTime library you mentioned, it was the culmination of a long thread (or threads) on this list a while ago. I think it's a pretty good stab at an API for manipulating and converting between: - absolute time (TAI) - UTC - times in calendar representation - timezones but it is missing - time offsets (eg. "1 day later") - a more complete/accurate timezone table - some way to update the leap second table - geographical time zones and probably some other things. my plan was that the whole "time offset" issue would be a layer on top of this library, as others have suggested. You can already do simple calculations using CalendarTime. The representation of absolute time could be revisited. What I mean by "geographical time zones" is some notion of a time zone that is independent of daylight savings time. The current TimeZone type is a fixed UTC offset (which I think is right), but there's no way to say "what's the local time in London at time T?". I probably won't be doing much to this library, but I think it's a good starting point for anyone who wants to explore further. Cheers, Simon